With the aim of characterizing the Mexican species of coralline algae from the genus Pneophyllum and their distribution, ten field trips in twelve localities were performed to collect species of Pneophyllum, from 1992 to 2004. Species were collected from Baja California, Baja California Sur, Sonora, Jalisco and Oaxaca at the Pacific coast of Mexico, and Quintana Roo at the Atlantic coast of Mexico. In addition, we complemented our study with observations of material currently deposited in different herbaria. Also, an extensive bibliographic revision of the genus Pneophyllum Kützing (Corallinales, Rhodophyta) in Mexico was done. Analysis of this information showed that this genus contains four species: P. confervicola (Kützing) Chamberlain, P. conicum (Dawson) Keats, Chamberlain & Baba, P. fragile Kützing and P. nicholsii (Setchell & Mason) Silva & Gabrielson. Furthermore, P. confervicola and P. fragile are distributed in both coasts at the Pacific and Atlantic shores of Mexico. Male and female reproductive structures of Pneophyllum are described and for the first time P. confervicola is recorded from the Atlantic coast of Mexico. Morphological descriptions, cytology, reproductive stage and photographs of the species examined are included.